1. Field of the Invention
This invention relates to tubing expansion. In particular, but not exclusively, the invention relates to diametric expansion of tubing downhole.
2. Description of the Related Art
One of the most significant recent developments in the oil and gas exploration and production industry has been the introduction of technology which allows for expansion of extended sections of tubing downhole. The tubing may take different forms, including but not restricted to: expandable casing, liner, sandscreen, straddles, packers and hangers. A variety of expansion methods have been proposed, including use of expansion cones or mandrels which are forced through the tubing. One difficulty which has been experienced with cone expansion is the high level of friction and wear between the surface of the cone and the inner surface of the tubing to be expanded.
It is among the objectives of embodiments of the present invention to obviate or mitigate this difficulty.